1. Field of the Invention
The present invention relates to a system and method for controlling home appliances, and in particular to a system and method for controlling a plurality of home appliances through a phoneline network alliance (PNA) provided in a building.
2. Description of the Related Art
A known home appliance networking system includes a plurality of home appliances interconnected via an internal network of a home or building, which is in turn connected to an external Internet network, thereby enabling a user to control the home appliances from anywhere inside or outside of the home or building.
In the known home appliance networking system, particularly, the user can access status information of a specific home appliance at any place inside of the home or building, and can control a specific home appliance using control means, such as a computer, at any place outside of the home or building. In this regard, the known home appliance networking system has obtained favorable responses from many consumers, and thus has become widespread in its application.
However, the above mentioned home appliance networking system has a disadvantage in that a local area network (LAN) must be constructed in the home or building to interconnect the home appliances via the internal network of the home or building and control the interconnected appliances in an integrated manner, resulting in a great cost being incurred.
In other words, in the known system, even though a user may wish to install home appliances in an existing building and control them via the internal network of the building, the user will be unable to control the home appliances so long as the internal network is not equipped with a system such as a LAN line. In order to control the home appliances, a separate network must be constructed in the building, thereby increasing the cost required for installing the home appliances.
Furthermore, even in a case where the internal network of the building is already equipped with a system such as a LAN line, the home appliances must be interconnected via hubs at limited distances, as shown in FIG. 1.
FIG. 1 shows a conventional home appliance control system. As shown in this drawing, an Internet network outside of a building (referred to hereinafter as an “external Internet network”) is connected to an Internet network I inside of the building (referred to hereinafter as an “internal Internet network”) via networking equipment such as a gateway N1 and a hub N2. The internal Internet network I includes a computing device B having such a public Internet protocol (IP) address as to be accessible by the external Internet network. The computing device B is adapted to assign respective private IP addresses to a plurality of home appliances A1, A2 and A3, and to transfer control information from the external Internet network to the home appliances A1, A2, and A3. To this end, the computing device B may include, for example, a server. A plurality of built-in home appliance communication modules C1, C2, and C3 are provided in the home appliances A1, A2, and A3, respectively, to convert the format of information, transmitted and received between corresponding home appliances A1, A2, and A3, and the external Internet network on the basis of the private IP addresses assigned by the computing device B, into standard formats of the corresponding home appliances and a standard format of the external Internet network, respectively. A plurality of hubs H1, H2, H3, and H4 are provided to interconnect the computing device B and the built-in home appliance communication modules C1, C2, and C3.
However, the interconnection of the computing device B and home appliance built-in communication modules C1, C2, and C3 using the plurality of hubs H1, H2, H3, and H4 is subject to limitations by Ethernet standards and hub structures. Because of such limitations, the number of communication modules connectable via the hubs is five at maximum and the distance between adjacent communication modules is 100 meters at maximum.